ALONG THE RIO GRANDE GORGE, N.M. — For the hunters and gatherers who called northern New Mexico home in prehistoric times, seeing Rocky Mountain bighorn sheep roam from the state's highest peaks down the 800-foot basalt cliffs that form the Rio Grande Gorge was part of life.

Petroglyphs chiseled into boulders up and down the river depict big-horned mammals, but it was long ago that the majestic animals disappeared from the area.

State and federal wildlife managers have been working years on the prospect of reintroducing the past, and they took a major step over the weekend as they lifted the latch on a livestock trailer and a group of bighorn sheep — after bit of hesitation — thundered out, scrambling one after the other up the rocks.

"They belong here. They're part of the diversity," Sam DesGeorges, head of the U.S. Bureau of Land Management's field office in Taos, said after Saturday's release. "Having the habitat and the animals that occupy that habitat is very important biologically."

The work continued Monday as Elise Goldstein, a bighorn sheep biologist with the New Mexico Department of Game and Fish, set up radio frequencies so the animals could be tracked and their progress monitored.

"It's exciting," she said of the restoration efforts. "It's really nice to be a part of something where the populations are doing well."

Millions of Rocky Mountain bighorns once roamed the West, but the fragile species quickly fell to frontier hunting and diseases introduced by domestic sheep. Today's bighorn populations either represent remnant herds or grew from reintroductions aimed at returning the bighorn sheep to their native range.

New Mexico has about 1,000 Rocky Mountain bighorn sheep, including herds in the Pecos, Wheeler and Latir Wilderness areas in the north, the Manzano Mountains southeast of Albuquerque and two areas in the Gila National Forest in the south.

Crews with the state Department of Game and Fish, the U.S. Forest Service and Taos Pueblo used drop nets baited with salt blocks to capture 25 sheep in the Pecos Wilderness early Saturday.

The animals were examined, given shots, outfitted with radio collars and trucked to the release site along the gorge just south of Taos. It marked the first time Rocky Mountain bighorn have been released on land managed by the BLM.

The sheep were let go midway along the 82-mile gorge, a sliver carved into layers of basalt by the Rio Grande, the nation's third-longest river.